The present invention relates to a method for making frozen confections containing uniformly coloured granules of ice scattered in the confection. The term "coloured granules of ice" herein used means the granules of ice prepared from blocks of ice made by freezing an aqueous coloured liquid containing colouring agent or flavouring agent such as syrups, coffee and fruit juices.
Hitherto, as a method for preparing ice creams having scattered or admixed with granules of ice, Nakayama et al. offers a method in which soft ice cream and granules of ice of about 1 to 350 mm.sup.3 in size are mixed and the mixture is frozen, in U.S. Pat. No. 4,031,262.
However, since in the above-mentioned method, in cases or preparing the granules of ice from the blocks of ice by crushing the blocks of ice and putting the crushed ice through a sieve to obtain the granules having a size within a certain range, the following defects are observed. That is, in cases of obtaining the coloured granules, (1) the blocks of ice made by freezing water coloured with one or more additives such as fruit juice, flavouring agents and edible colours have these additives concentrated in the center part of the blocks, and accordingly it is extremely difficult to obtain the blocks of ice uniformly coloured. Therefore, it is also extremely difficult to obtain the uniformly coloured granules of ice by crushing such as irregularly coloured block. And, (2) since the granules of ice obtained by crushing the blocks of ice have their surface melted, the granules adhere mutually to cause blocking, thus making the shifting of the granules into a size within a range very difficult.
Accordingly, the ice cream with granules of ice or coloured granules of ice is not possibly prepared in a continuous manner industrially and effectively by the method of U.S. Pat. No. 4,031,262.
While, U.S. Pat. No. 3,360,384 discloses a method for preparing an edible frozen product, in which discrete sub-cooled particles obtained by making an edible material such as juices, syrups and purees into contact with a cryogenic refrigerant to be sub-cooled at a temperature of lower than -100.degree. F. (-73.degree. C.) are combined with ice cream. However, since the sub-cooled particles have been prepared by making the material such as juices and syrups directly into contact with the cryogenic refrigerent at a temperature of lower than -100.degree. F., they are fragile, and moreover, since these sub-cooled particles are mixed with ice cream at their state of being kept at an extremely low temperature of, for instance, -320.degree. F. (-195.degree. C.), the ice cream is to be excessively cooled, and as a result, there is a defect of deterioration of the texture of the ice cream product.
Furthermore, as a method of preparing the granules of ice, a method of spraying water within a super-cooled chamber or a method of freezing water by injecting water into a plate having a plurality of hollows suitable for shaping water into the form of granule is offered. However, these methods are not suitable for mass production in an industrial scale.
We, the inventors of the present invention, after studying the methods for preparing the frozen confections containing granules of ice, particularly the uniformly coloured granules of ice scattered throughout the same effectively in a manner of mass production and continuously have found that in the case of freezing an aqueous coloured liquid containing a stabilizer, the block of ice uniformly coloured in naked eyes is obtainable unexpectedly, and that in the case where the ice pieces obtained by crushing the thus obtained block are brought into contact with a refrigerant such as liquid nitrogen to refrigerate the surface of the ice pieces before sifting the pieces, the formation of the mutual adhesion of the pieces is prevented and the ice pieces having a brilliancy such as jewels are obtainable, and have been lead to the present invention.